1. Field of the Invention
This invention is related to a cautery hemostatic unit which is deliverable through an endoscope and is to be used for stopping hemorrhage by cauterizing a bleeding wound.
2. Related Art Statement
In recent years, endoscopes which permit diagnosing and/or taking therapeutic measures in deep regions of the body, without major incision from the external side of the body, by inserting a slender probe therein, have been used widely in various medical fields.
These endoscopes are designed so that an adequate medical instrument can be inserted into the hollow channel which passes therethrough in order to enable the surgeon to take various therapeutic measures in addition to general observations.
A laser coagulator which irradiates laser beams to coagulate the bleeding site is used as a means to stop bleeding in such cases as removal of a tumor, etc., but the cost is expensive and the use of such a device requires a great deal of skill and, besides, it is highly risky.
For such reasons, an instrument which uses a heater probe which can be delivered therethrough, and which permits coagulating the bleeding site to which this heater probe is applied, by electrically charging a heating coil assembled in the distal extremity of this heater probe, has been developed.
However, such an instrument has a low heat response which does not insure quick heating and subsequent cooling and, thereby, heat penetrates into the surrounding tissues and necrosis of tissues in other sites than the site to be treated may occur until the coagulation is achieved or until the heater probe is cooled after coagulation.
Japanese Patent Application No. 69556/1983 discloses a high-speed heat cautery probe which uses a cautery probe deliverable through a channel in an endoscope and a heater element of good heat response to insure rapid heating and subsequent cooling. This prior art device is equipped with a nozzle to jet out washing solution which is fed through a catheter by pressure, and functions to facilitate the discovery of bleeding by washing blood away from the wound.
However, for the above-mentioned prior art, the composition and shape of the nozzle to jet out washing solution along the direction of outer axis are not published. Besides, this prior art incorporates an electric system to supply electricity to the cautery probe and a water channel to feed washing solution by pressure, but no separate composition of these two channels is taught.
The distal end of the heating cautery probe has a hollow cylindrical cap terminating in a hemispherical surface. The cap is coated with a non-adhesive material and joined by soldering to the end of the slender sheath just distal to the end of the nozzle opening. Because of the proximity of the soldered joint to the end of the nozzle, special care must be exercised to keep solder out of the nozzle.
Furthermore, the non-adhesive coating on the outer surface of the above-mentioned cap will be peeled off gradually by repeated use and the non-adhesive property will eventually be lost. Therefore, it is necessary to regularly recoat the cap with non-adhesive material. However, if non-adhesive coating (for example Teflon coating) is done on the above-mentioned cap without separating it from the probe, the zener diade which is incorporated as heating element therein will be destroyed or damaged because the cautery temperature must be increased above 400.degree. C. For this reason, it is necessary to separate the cap from the probe every time a non-adhesive coating is applied, which, as described, is a tedious process.